1. Field of the Invention
The present invention relates to a carbon nanotube, an electron emission source including the carbon nanotube, and an electron emission device including the electron emission source. In particular, the present invention relates to a carbon nanotube in which a difference between a thermal decomposition initiation temperature and a thermal decomposition termination temperature is less than or equal to 250° C., an electron emission source including the carbon nanotube, and an electron emission device including the electron emission source.
2. Description of the Related Art
Electron emission devices are displays that create images by emitting light by having phosphors in a phosphor layer of an anode plate collide with electrons emitted from electron emission sources of a cathode under an electric field generated when a voltage is applied to the anode and the cathode.
Carbon-based materials, including carbon nanotubes having good electron conductivity, have properties such as a good field enhancement effect, low work function, good field emission property, low driving voltage, and an ability to be fabricated over a large area. Therefore, carbon-based materials are good electron emission sources for electron emission devices.
Korean Patent Laid-Open Publication No. 2002-0040133 discloses a method of growing carbon nanotubes for field emitters of a field emission display, e.g., a method of growing carbon nanotubes for field emitters of a field emission display, including forming a Fe—Ni or Ni—Fe alloy layer on a support substrate, forming a catalytic metal layer on the alloy layer, and growing the carbon nanotubes on the catalytic metal layer.
Japanese Patent Laid-Open Publication No. 2003-059436 discloses a cathode substrate and an anode substrate for a carbon nanotube field emission display and a method of forming a cathode substrate. According to this patent publication, the cathode substrate includes a glass substrate, a cathode layer patterned into a plurality of electron emission areas on the glass substrate, and a plurality of carbon nanotube structures grown on the electron emission areas.
Carbon nanotubes having the above-described carbon nanotube structures and other common carbon nanotube structures decompose at a temperature of approximately 400° C. or greater. The thermal decomposition of carbon nanotubes causes a loss of carbon nanotubes when the upper and lower plates are sealed during fabrication or when a carbon nanotube paste is fired, thereby reducing an amount of electron emission and a lifetime of the cathode.